document.write( "Question 864459: A family drives at 55 kilometers an hour toward a city 660 kilometers away. A second family leaves an hour later and drives 60 kilometers an hour. Which family will arrive at its destination first, and how much later does the other arrive? \n" ); document.write( "
Algebra.Com's Answer #521035 by LinnW(1048)![]() ![]() You can put this solution on YOUR website! Let's find out how long it will be until the two families are at the \n" ); document.write( "same location. \n" ); document.write( "At some distance d , we have for the first family \n" ); document.write( "d = 55 km * t + 55*( 1 hour ) \n" ); document.write( "and for the second family, \n" ); document.write( "d = 60 km * t \n" ); document.write( "So 55*t + 55 = 60*t \n" ); document.write( "subtract 55t from each side \n" ); document.write( " 55 = 5t \n" ); document.write( "divide each side by 5 \n" ); document.write( " 11 = t \n" ); document.write( "So for the first family d = 55*11 + 55 = 660 \n" ); document.write( "The first family has traveled for a total of 12 hours, \n" ); document.write( "The first hour before the second family started plus 11 hours. \n" ); document.write( "The second family travels the 660 miles in 11 hours. \n" ); document.write( "************ \n" ); document.write( "The two families arrive at the same time. \n" ); document.write( " |